Book Image

Mastering JavaScript Functional Programming - Second Edition

By : Federico Kereki
Book Image

Mastering JavaScript Functional Programming - Second Edition

By: Federico Kereki

Overview of this book

Functional programming is a paradigm for developing software with better performance. It helps you write concise and testable code. To help you take your programming skills to the next level, this comprehensive book will assist you in harnessing the capabilities of functional programming with JavaScript and writing highly maintainable and testable web and server apps using functional JavaScript. This second edition is updated and improved to cover features such as transducers, lenses, prisms and various other concepts to help you write efficient programs. By focusing on functional programming, you’ll not only start to write but also to test pure functions, and reduce side effects. The book also specifically allows you to discover techniques for simplifying code and applying recursion for loopless coding. Gradually, you’ll understand how to achieve immutability, implement design patterns, and work with data types for your application, before going on to learn functional reactive programming to handle complex events in your app. Finally, the book will take you through the design patterns that are relevant to functional programming. By the end of this book, you’ll have developed your JavaScript skills and have gained knowledge of the essential functional programming techniques to program effectively.
Table of Contents (17 chapters)
Technical Requirements

Logical higher-order functions

Up to now, we have been using higher-order functions to produce new results, but there are also some other functions that produce logical results by applying a predicate to all the elements of an array. (By the way, we'll be seeing much more about higher-order functions in the next chapter.)

A bit of terminology: the word predicate can be used in several senses (as in predicate logic), but for us, in computer science, it has the meaning of a function that returns true or false. Okay, this isn't a very formal definition, but it's enough for our needs. For example, saying that we will filter an array depending on a predicate just means that we get to decide which elements are included or excluded depending on the result of the predicate.

Using these functions implies that your code will become shorter: you can, with a single...